1. Field of the Invention
The invention is directed to four mechanically actuated hydraulic valves which rephase the controlling/controlled lifting hydraulic cylinder pairs in a folding agricultural implement frame.
2. Description of the Prior Art
Typically agricultural implements, such as planters, grain drills and tillage equipment, are towed behind a draft vehicle to perform a specified operation. The support frames on which these implements are mounted are getting larger and larger. This enables the farmer to cover a wider area with each pass across the field.
The implement frames extend perpendicular to the fore/aft draft axis of the draft vehicle. Although these frames work well in the field in their working configuration, they become difficult to transport from field to field. As such many of these frames have folded transport configurations in which their transverse swath is reduced. One example of such a frame, is the front fold implement frame illustrated in U.S. Pat. No. 4,607,708. In this patent the implement frame is provided with two wing sections that fold forwardly so that they lie along the fore/aft draft axis of the draft vehicle.
It is also important that the row markers located at the end of the implement frame be locked into their retracted transport condition when the implement frame is folded into its transport configuration.